The number of 6 digit numbers that contains 6 exactly once is _________ .

Explanation

To solve the problem of finding the number of 6-digit numbers that contain the digit '6' exactly once, we can break it down into a few steps:

### Step-by-Step Solution:

1. **Understanding the Structure of a 6-Digit Number**:
A 6-digit number can be represented as \(d_1 d_2 d_3 d_4 d_5 d_6\), where \(d_1\) is the first digit and cannot be '0' (as it would then be a 5-digit number).

2. **Case 1: '6' in the First Position**:
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